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    SubjectRE: [PATCH 6.0 681/862] wifi: rtw88: phy: fix warning of possible buffer overflow
    Date


    > -----Original Message-----
    > From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    > Sent: Wednesday, October 19, 2022 4:33 PM
    > To: linux-kernel@vger.kernel.org
    > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; stable@vger.kernel.org; Kevin Yang
    > <kevin_yang@realtek.com>; Ping-Ke Shih <pkshih@realtek.com>; Kalle Valo <kvalo@kernel.org>; Sasha Levin
    > <sashal@kernel.org>
    > Subject: [PATCH 6.0 681/862] wifi: rtw88: phy: fix warning of possible buffer overflow
    >
    > From: Zong-Zhe Yang <kevin_yang@realtek.com>
    >
    > [ Upstream commit 86331c7e0cd819bf0c1d0dcf895e0c90b0aa9a6f ]
    >
    > reported by smatch
    >
    > phy.c:854 rtw_phy_linear_2_db() error: buffer overflow 'db_invert_table[i]'
    > 8 <= 8 (assuming for loop doesn't break)
    >
    > However, it seems to be a false alarm because we prevent it originally via
    > if (linear >= db_invert_table[11][7])
    > return 96; /* maximum 96 dB */
    >
    > Still, we adjust the code to be more readable and avoid smatch warning.

    Like Pavel mentioned [1], this patch is to avoid smatch warning, not a really
    bug. So, shouldn't take this patch.

    [1] https://lore.kernel.org/linux-wireless/20221018093921.GD1264@duo.ucw.cz/

    >
    > Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
    > Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
    > Signed-off-by: Kalle Valo <kvalo@kernel.org>
    > Link: https://lore.kernel.org/r/20220727065003.28340-5-pkshih@realtek.com
    > Signed-off-by: Sasha Levin <sashal@kernel.org>
    > ---
    > drivers/net/wireless/realtek/rtw88/phy.c | 21 ++++++++-------------
    > 1 file changed, 8 insertions(+), 13 deletions(-)
    >
    > diff --git a/drivers/net/wireless/realtek/rtw88/phy.c b/drivers/net/wireless/realtek/rtw88/phy.c
    > index 8982e0c98dac..da1efec0aa85 100644
    > --- a/drivers/net/wireless/realtek/rtw88/phy.c
    > +++ b/drivers/net/wireless/realtek/rtw88/phy.c
    > @@ -816,23 +816,18 @@ static u8 rtw_phy_linear_2_db(u64 linear)
    > u8 j;
    > u32 dB;
    >
    > - if (linear >= db_invert_table[11][7])
    > - return 96; /* maximum 96 dB */
    > -
    > for (i = 0; i < 12; i++) {
    > - if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][7])
    > - break;
    > - else if (i > 2 && linear <= db_invert_table[i][7])
    > - break;
    > + for (j = 0; j < 8; j++) {
    > + if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][j])
    > + goto cnt;
    > + else if (i > 2 && linear <= db_invert_table[i][j])
    > + goto cnt;
    > + }
    > }
    >
    > - for (j = 0; j < 8; j++) {
    > - if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][j])
    > - break;
    > - else if (i > 2 && linear <= db_invert_table[i][j])
    > - break;
    > - }
    > + return 96; /* maximum 96 dB */
    >
    > +cnt:
    > if (j == 0 && i == 0)
    > goto end;
    >
    > --
    > 2.35.1
    >
    >
    >
    >
    > ------Please consider the environment before printing this e-mail.
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